JEFFERSON COUNTY. 
381 
But three or four uplifts in succession, varying from twenty-five to thirty-five feet in height, 
in which the different strata composing the rock appear, furnish an opportunity for an exami¬ 
nation of a large portion of the rock. This mass, which succeeds the potsdam sandstone, 
continues the surface rock only one mile and a half, when it is succeded by the birdseye. 
It dips generally to the south, and its principal natural joints run north and south, but the 
ranges of low hills of this portion of the county have a direction northeast and southwest. 
From this point, about four miles south of Theresa falls, the calciferous extends to the east and 
west; and taking the whole mass into view, it forms a belt traversing the entire width of the 
county, from near the Natural bridge on the east, to French creek on the west. This belt is 
from one and a half to four miles wide; its northern outcrop resting on the potsdam sand¬ 
stone, while at the south it passes beneath the birdseye. Not far south from the first uplift 
which exposes the calciferous sandrock, on the road leading from Theresa to Watertown, the 
drab-colored layers form a large proportion of the mass. They contain masses of calcare¬ 
ous spar and sulphate of strontian, and disseminated particles of sulphuret of iron. These 
layers appear to be adapted to form the usual hydraulic lime. The portion of the calciferous 
exposed to inspection upon this road, is about sixty feet thick ; and so far as my observations 
extended, it is destitute of fossils. The development of this rock in this county appears to be 
confined to the lower portion, or we do not discover those beds which, in other places, belong 
to the upper part. Some of them may exist concealed beneath the drift and soil. 
The Calciferous sandrock, as it is exposed between French creek and Depauville. 
On this route we traverse this rock from west to east. The first appearance is one and a 
half miles east of French creek, on the summit of a hill; it here succeeds the sandy variety 
of the potsdam, which has already been noticed. The fucoidal layers make their appearance 
first; they are very siliceous, and most of these vegetable forms are casts, and destitute of 
an organic structure. By far the largest portion have disappeared, leaving simply cylindrical 
but branching perforations in the rock. This mass is about ten feet thick. 
Proceeding east, we soon reach the drab colored layers of the rock, quite similar to those 
already spoken of as existing on the Watertown road. Here they contain a greater amount 
of sulphate of strontian and calcareous spar. The rock continues to Depauville, where it is 
quarried for hydraulic lime. The lower strata at this place are evidently quite siliceous, or 
sandy. At Depauville the birdseye appears, but it only occupies the highest grounds. The 
union or junction of the two rocks is therefore formed at this place. 
On a review of the characters of the calciferous sandrock, as it presents itself in the diffe¬ 
rent portions of the Second district, we find that it is uniform in its composition and structure. 
Corresponding portions agree in most respects with those which have been noticed under the 
different counties. The fucoidal layers every where are the same, with the exception of a 
mass at Chazy, which being much more argillaceous than usual, may possibly be a distinct 
additional mass. The drab colored layers are specially uniform, being in all respects iden¬ 
tical both in composition and color, and also destitute of fossils. When portions of this rock 
